Method of sinking metal piling for cofferdams



Feb. 25, 1941 R. w. FXEROH METHOD OF SINKING METAL FILING FOR COFFERDAMS 2 Sheets- Sheet l Filed March 31, 1959 Feb. 25, 1941. R. w.- hERoH 2232,1345

METHOD OF SINKING METAL FILING FOR COFFERDAMS Filed March 31, 1939 2 Shets-Sheet 2 Patented F eb. 25, 1941 COFFEE/DAMS Robert W. Fieroh, Chicago, Ill. Application March 31, 1939, Serial No. 265,167

7 Claims.

The main object of this invention is to provide an improved method of penetrating underground hard materials, such as limestone, sandstone, conglomerate, shale, boulders, shelf rock,

bed rock, etc., which are encountered in driving down steel piling for cofferdams.

The usual method of building a cofierdam, surrounding a construction project, whether of square, circular or irregular shape, for bridge piers, intake crib houses for water supply, foundations for power houses, or manufacturing plants located along rivers or streams or over water bearing soils, is to first make an excavation to slightly above the water line, then erect therein a template frame work of timber or steel or both to outline the location of the cofferdam wall or walls, and then set around the frame work the steel piling forming the cofferdam. The framework acts as part of the interior bracing 20 when the excavation within the enclosure proceeds, other horizontal bracing being placed as the excavation is carried down. After all the steel piling has been placed around the framework it is driven in successive steps around the 25 enclosure until it encounters hard obstructions of the kind above enumerated. Since bed rock is usually overlaid with shale, conglomerate of very hard rocks, and water bearing sand, and is 3 driving of the co-fferdam walls to secure a seal sand creeping into the excavation beneath the walls as excavation within the walls proceeds, thus causing much expense and loss of time.

By my present invention this hard materialis drilled and broken up to form a' comparatively easy path for the steel piling before the latter is driven through it and into bed rockpz To facilitate a clear understanding of the method and the pref-erred'means. for practicing it, I have included in this specification the ac- 50 companying drawings, in which Fig. 1 is a fragmentary plan view of a corner of the excavation and the template frame therein, showing a pair of drill guides, drilled holes, and a, corner piling and a sheet piling occupying 55 the drilled holes.

seldom level, it'is extremely difiicult by further end if driven further.

Fig. 2 is a fragmentary plan view, similar to Fig. 1, showing twoconnected units of sheet piling in place and a corner drill guide for the erection of a cross sheet piling wall between two template frames. 5

Fig. 3 is a view partly in vertical section on the line 3-3 of Fig. 1, showing the lower end portions of the corner piling, the sheet piling, and the drill guide with a drill bit in one of its tubes; the view also showing typical formations encountered down tobed rock.

Fig. 4 is a cross section through a corner drill guide, showing temporary guides inserted in two tubes thereof to guide the corner piling into drilled holes as it is driven down.

Fig. 5 is a view partly in elevation and partly in vertical section showing three sheet piling units interlocked edge to edge and occupying different positions in the sinking operation, and also showing in vertical section a drill guide unit interlocked edgewise with the last entered and highe'st'unit of the sheet piling. r

Describing the improved method of building the cofierdam in connection with the drawings, an excavation, a corner portion of which is indicated by the irregular lines ID in Figs. 1 and 2, is first made down to preferably a short distance above the water line, and in this excavation is erected the template framework or bracing II, which outlines the location of the cofierdam wall or walls and forms a guide and support for the instrumentalities used in building the cofferdam." In the case of a rectangular structure, such as is illustrated in the drawings, a rectangular drill guide designated as an entirety by I 2 is set in place at the corner of the framework, this drill guide comprising three tubes, l3, l4 and 15 welded to each other sidewise .by narrow necks IS, the central tube l4 being equipped with a pair of coupling claws l1 and I8, and this drill guide is driven down until it strikes an obstructing stratum such as might damage its lower The tubes of the drill guide are then cleaned out, which may be readily doneby pipes entered therein for the admission "of jets of water, air under pressure, or a well bucket. A drill is then successively entered into the tubes and operated to drill holes through the several obstructing strata down into bed rock. Any practical form of drill may be employed, Fig. 3 showing a drill l9 of a type extensively used in sinking oil wells. The particles of rock broken up and more or less pulverized by the drill are then blown out in the manner'above described, and then a pair of guide claws and 2I each having integral with the shank of the claw a semi-tubular base 22 that fits the inner surface of a tube of the drill guide are dropped into the end tubes I3 and I5 of the drill guide I2, as shown in Fig. 4. The corner drill guide I2 is then pulled out, leaving the claws 2D and 2I in place, and a rectangular corner pile 23 is then entered into the three holes 24, 25 and 26 formed by the drill guide as shown in Fig. 1, with its claws engaged with the claws 20 and 2I in the manner indicated in Fig. 4, and

driven down to about the top of the holes such.

as 25 and 26' formed by the drill, as shown in Fig. 3. The temporary guide claws 20, and 2|. which serve to maintain the two Wings of the corner pile 23 parallel with the sides of the template II during the driving operation, are then pulled out. The work is then continued from either end of the corner pile 23 as follows:

A rectilinear drill guide, designated as an entirety by 21; and comprising three tubes 28, 29' and 3! connected to each other in a straight row by narrow necks 3| is then placed against the side of the framework II, with a claw 32 on the tube 28 engaged with and guided by a claw 33 on the adjacent wing of the corner pile 23, and this drill guide is driven down until it strikes an obstructing stratum in the same way as the corner drill guide I2 was driven. The tubes 28, 29 and 36 are emptied by a pressure jet, or otherwise, and the drill I9 is then successively entered into the tubes and operated to drill holes through the several obstructing strata down into bed rock, these drilled holes being indicated at 34, 35' and 36' in Fig. 3, which drilled holes are continuous with and below the drill guide holes 34, 35 and 36 shown in Fig. l. The drill guide 21 is then pulled out, and a sheet pile unit 3'l'formed with claws 38 and 39 on its vertical edges is then driven down with its claw 38 interlocked with the claw 33 of the corner pile to approximately the distance indicated in Fig. 3. The Wall pile 37 having thus been interlocked with the corner pile 23, the latter may then be driven further down leaving the wall pile 3'I temporarily in the partially driven position indicated in Fig. 3.

By the use of the same drill guide 21 a second group of three holes similar to and next beyond the group 34, 35 and 35 is formed, and then, by the use of the drill I9 additional drilled holes 40, 4! and 42 (Fig. 3) are formed, as continuations of the drill guide holes, in the rocky sub-strata. A second sheet pile unit 43 (Fig. 5) similar to unit 3'! is next introduced with its claw 44 interlocked with the claw 39 of unit 31, and driven down. At this time the corner unit 23 may be driven the remainder of the distance into bed rock. Another row of three holes having been prepared beyond the sheet pile unit 43, another sheet pile unit 45 may be entered with its claw 46 slidingly engaged with the claw 47 of unit 43, whereupon unit 31 may be further driven into bed rock, as shown in Fig. 5.

In this manner, the remaining units of the cofferdam wall are successively erected, each unit. as it is entered and driven down, being guided and maintained vertical by engagement of its claw with the cooperating claw of the preceding unit. as indicated in Fig. 5, the remaining corner piles 23 not requiring the use of temporary guide claws such. as 20 and 2I.

As will be evident from Figs. 3 and 5, the holes formed by the drills are not contiguous or tangent toeach other, but are necessarily separated by narrow vertical strips of earth and mineral matter indicated by 48 in Figs. 3 and 5; but these narrow walls are readily cut through and broken down by the lower end edges of the pile units as the latter are driven down.

From the foregoing it will be seen that, if the coiierdam wall is started at one point and continued entirely around the template framework to the same point, but a single corner drill guide I2 and a single wall drill guide 21 are required. And it is further noted that these parts do not constitute any elements of the cofferdam wall itself, but are merely tools used in the erection of the cofierdam wall. If the erection of the wall is carried on simultaneously both ways from two starting points (as might be done in the case of the rectangular wall herein illustrated), a correspondingly larger number of drill guide units, would, of course, be required.

In cases where the cofiz'erdam iscircular, oval, or of other curved form, the rectangular drill guide and rectangular corner piles are not required, the interlocking claws of the drill guide units affording the necessary flexibility to secure the curvature of the cofferdam wall.

The purpose of the coupling claws such as I1 and IB on the corner drill guide I2 is to aid in accurately positioning such drill guide relatively to a previously completed portion of the cofferdam wall; this being mainly useful where, as illustratedin Fig. 2, a cross wall is to be erected between a pair of template frameworks.

The holes are drilled and the piling driven a sufiicient distance below the interior footing to give a proper seal against water leakage and a toe for piling in rock, if necessary, to withstand outside pressure against the steel piling, thereby eliminating the necessity of providing a bottom set of bracing, and providing clear working space for excavating and concreting the bottom. The piling unit interlocks completely fill the drill holes, adding stiffness to the structure. This driving method also increases the salvage value of the pilingby eliminating damage of the piling due to excessive pounding against rocks, which not only causes bent and deflected piling, but renders it diflicult or impossible of pulling out.

Pulling holes such as 49 (Fig. 5) are provided in each piling unit to receive grab hooks for pulling out the wall units, after the cofferdam has served its purpose. Similar grab hook holes 50 are formed in the drill guides.

From the foregoing it will be seen that the present invention facilitates and speeds the erection of coiferdams by preparing a path through difficult strata for the easy driving of the wall piling units, and it prevents distortion of and other damage to the said units such as makesthem diflicult to withdraw after the cofferdam is no longer required and practically destroys their re-use or salvage value. Changes in the order of the steps'or operations hereinabove recited as well as in the detail structure of the tolls used, such as the drill guides and drills, maybe resorted towithin the contemplation and coverage of the claims.

I claim:

1. A method of building cofferdams, which comprisesmaking an excavation, erecting a template framework in said excavation, drilling closely adjacent holes through hard conglomerate and into bed rock below the edges of said framework, and then driving cofferdam wall units side by side around the sides of said framework through said holes and the narrow walls between them and into bed rock to form a seal.

2. A method of building cofierdams, which comprises making an excavation, erecting a template framework in said excavation, placing multiple tube drill guides around the sides of said framework and driving them down to an underlying hard conglomerate, removing the detritus from the tubes of said guides, entering a drill through said tubes and drilling holes through said conglomerate into bed rock, removing said drill and drill guides, and then driving cofierdam wall units side by side around the sides of said framework through said holes and into bed rock to form a seal.

3. A method as defined in claim 1, wherein the cofierdam units are driven successively and each unit is guided in its descent by sliding edgeto-edge engagement with the next preceding unit.

4. A method as defined in claim 1, wherein the cofferdam units are driven successively and each unit is guided in its descent by sliding interlocked engagement with an edge of the next preceding unit.

5. A method as defined in claim 1, wherein the colferdam units are driven one at a time with each unit guided in its descent by sliding interlocked engagement with an edge of the next preceding unit, and each unit is driven to bed rock in two or more stages.

6. A method as defined in claim 2, wherein narrow walls between adjacent drilled holes are broken down by a cofierdam wall unit driven into said holes.

7. A method as defined in claim 1, wherein the cofferdam units are driven with each unit guided in its descent by sliding interlocked engagement with an edge of the next preceding unit, and said units are successively driven to bed rook each in two or more stages.

ROBERT W. FIEROI-I. 

